Peerless in the Premiership, Arsenal are finally showing the potential to conquer the continent as they took a significant step towards the Champions League quarter-finals.

With Robert Pires striking an 80th-minute winner away to Celta Vigo in this last 16 first leg tie, Arsenal secured their first-ever victory in Spain.

However, this match was essentially much Edu about something as the Brazilian midfielder struck the two goals which put Arsenal on course for their last 16 first leg success.

Not that the Arsenal fans were able to sing 'there's only one Edu'. For there were, in fact, two of them on the pitch and both were 25-year-old Brazilians.

Even more amazingly, it was Celta Vigo's Edu who initially put the Spanish side level before Jose Ignacio struck their second equaliser on 64 minutes.

Indeed, while Arsenal have been something of a Jekyll and Hyde team in the competition this season, rarely have they shown both sides of their character in the same match.

While they constantly looked a threat going forward, Wenger will be duly concerned at his side's uncharacteristic defensive lapses as they looked vulnerable in the air.

Other sides will punish Arsenal even more severely for such uncertainty, although they always retain the ability to outscore any opponents with their prolific attacking potential.

In the absence of Dennis Bergkamp, who does not fly, Jose Reyes had started alongside Thierry Henry for the first time in his Champions League debut.

The 20-year-old Spain international even had the first chance of the game, only to shoot straight at keeper Pablo Cavallero from Henry's neat flick.

While Celta made most of the early running, with full-back Gael Clichy producing a fine covering tackle on former Aston Villa striker Savo Milosevic, Arsenal were ahead after 16 minutes, albeit with a stroke of considerable good fortune.

Pires's free-kick flew across the penalty area and was unconvincingly nodded goalwards by Arsenal midfielder Edu only to strike defender Juan Velasco.

The Brazilian then flung himself at the loose ball, catching keeper Cavallero with a painful blow to his face as the ball deflected into the net, seemingly off defender Berizzo.

Cavallero needed lengthy treatment to a bloodied nose and forehead before play eventually resumed and it was not long before Celta were level.

Bizarrely, it was their own Edu who scored it on 26 minutes as he rose unchallenged to head past keeper Jens Lehmann as Silvinho produced the pin-point free-kick delivery against his former team.

Arsenal were by no means at their most convincing and their normally solid defence was under severe strain as Lehmann had to dive full-length to parry a fierce drive by Edu.

Celta also claimed a penalty when Silvinho charged onto Alexander Mostovoi's flick and plunged to the floor but referee Anders Frisk correctly ruled that Kolo Toure was more the victim than the perpetrator as he was left winded by the Brazilian.

Arsenal were fortunate not to fall behind just 30 seconds after the restart as Mostovoi's header thumped against the crossbar from Edu's inviting cross.

Jose Ignacio then burst into the penalty area and shot into Lehmann's midriff, while Edu continued to give 18-year-old Clichy a torrid time.

Arsenal were nevertheless starting to threaten on the break and while Cavallero parried an effort from Reyes, Henry skewed his follow-up effort wide.

The Gunners' Edu then seized the moment with a goal of sheer individual quality as he side-stepped his way past three opponents before steadying himself and curling a superb shot into the top corner.

Once again, however, Arsenal's lead did not last long, with Celta level for a second time after 64 minutes. Again, the danger came from a cross.

Jose Ignacio was left with far too much time and space to spin onto Fernandez Sergio's downward header from a corner and, although Lehmann got his fingers to the ball, it sneaked inside the post.

Back came Arsenal once again though, with Pires and Henry combining to slice their way through the Celta Vigo defence with 10 minutes left before Pires finished with aplomb into the far corner.

It was by no means a convincing display but the result was all-important. The quarter-finals now surely beckon.

Teams

Celta Vigo Cavallero, Velasco, Sergio, Berizzo, Silvinho, Luccin, Jose Ignacio, Angel (Vagner 64), Mostovoi, Edu (Pinilla 75), Milosevic.

Subs Not Used: Pinto, Caceres, Contreras, Mendez, Jandro.

Booked: Silvinho.

Goals: Edu 27, Jose Ignacio 64.

Arsenal Lehmann, Lauren, Toure, Campbell, Clichy (Bentley 89), Ljungberg (Cygan 90), Vieira, Edu, Pires, Henry, Reyes (Kanu 78).

Subs Not Used: Stack, Keown, Hoyte, Fabregas Soler.

Booked: Edu, Henry.

Goals: Edu 18, 58, Pires 80.

Att: 21,000

Ref: Anders Frisk (Sweden).